1. Field of the Invention
The present invention relates to a print control apparatus and print control method for generating print data based on rasterized data and outputting it to a printing apparatus, a program, and a storage medium.
2. Description of the Related Art
In general, a printer driver performs color correction and color conversion of color data from an application into color data printable by a printer. The printer driver quantizes the color data, and generates image data to be output to a printer. The printer driver receives R, G, and B (Red, Green, and Blue) color data from the application, and outputs C, N, Y, and K (Cyan, Magenta, Yellow, and blacK) color data to the printer. The printer driver is installed as software corresponding to each printer in a host computer, and performs print control processing in color printing under the control of an operating system (OS).
To speed up print control processing in color printing, the following method has already been proposed (see, e.g., patent reference 1: Japanese Patent Laid-Open No. 8-90839). More specifically, the printer driver directly generates print data from rasterized data generated from monochrome binary (1-bit) information when printing data formed from only black such as a character or line. This implements print control processing free from color processing and quantization, and increases the efficiency and speed of print control processing.
An inkjet printer often determines, from print setting information set at the start of printing, whether print control processing based on 1-bit rasterized data is available. Only when it is determined that this processing is available, the inkjet printer executes 1-bit rasterization.
Another method is to rasterize both RGB data and monochrome binary data and switch rasterized data in accordance with a rendering instruction (see, e.g., patent reference 2: Japanese Patent Laid-Open No. 2004-102585). However, it is determined whether 1-bit rasterized data is available.
The reason why it must be determined whether 1-bit rasterization is available is that it is convenient in the following cases to perform processing from RGB multilevel rasterized data even for data such as a black character or black line which can be rasterized into 1 bit:
(1) A case where print setting information represents a high black ink density and the amount of black ink discharge is decreased to prevent ink overflow on a print medium.
(2) A case where special processing is necessary to emphasize a black print result by discharging C, M, and Y inks over black ink.
As described above, a conventional printer driver determines the rasterization method based on print setting information set at the start of printing. A printer driver for a printer having a function of detecting the type of print medium also generally executes rasterization corresponding to print setting information after detecting the type of print medium. In general, the printer driver uses expected rasterized data. In other words, the printer driver does not receive rasterized data incompatible with a rasterization method designated by the printer driver at the start of printing. Upon receiving different rasterized data, most printer drivers stop print information processing.
As a system function, a function of switching between 1-bit rasterized data and RGB multilevel rasterized data is prepared even for print control processing using a spooler function on an OS on which the printer driver runs, and a module serving as the center of the printer driver. This function can increase the development efficiency of the printer driver and the efficiency and speed of driver processing.
However, the switching function of the system can be designated only at the start of print processing when speeding up print control processing using this switching function.
That is, high-speed processing can be achieved by validating the switching function at the start of printing and receiving 1-bit rasterized data by the printer driver. However, the switching function cannot be used in the following cases under limitations:
(1) A case where, even if a printer has a function of automatically detecting a print medium, and at the start of printing, setting information represents that 1-bit rasterized data is available, no 1-bit rasterized data can be used for the type of print medium automatically detected upon receiving rasterized data. For such a printer, the rasterized data switching function must be invalidated in advance.
(2) A case where a printer has a function of changing the density and color balance of a print result, and no setting information is applicable as the rasterized data switching function setting condition because the setting information is unique to the printer driver. If it cannot be determined at the start of printing whether to validate or invalidate the rasterized data switching function, the rasterized data switching function must be invalidated in advance.